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1986 YAMAHA 175hp problems

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madetdb8

New member
hi people, new to this website and new to marine field. thanks for help.
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26062011 008.jpgi recently had a yamaha 175, i was told the gearbox and middle unit is 2000 and the power head is 1986. i was wondering how they did that.
anyway, i had this motor test run last nite with water muffle at home. it was idling good and run pretty hard when the fast idle lever is pulled up.
today, i had my boat down on the water. it was ok for the first couple of minutes at 1/4 throttle.(due to the speed limit in the port)
But after 5 minutes, the engine starts to vibrate badly and can not rev up. and of course i feels the power output was even worse than my old 50hps.
last nite, when i was doing the test, the oil warning light was on. i thought that was because of the bad wiring. and today, the remote starts beep once i turn the key on. and there is a warning light( a circle with a flat bar at lower position,i dont know what is this) come up and the oil light disappear.
once the boat is out water, i see heaps black oil drops come out the propeller with the water.
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Difference:
the external oil container had a little bit red colour oil(around a liter) in it yesterday.
and before i went on water today, i fill up the external oil container with Valvoline NMMA TC-W3 (synthetic enhanced marine oil)
yesterday, the fuel tank had around 30L of 1:50 mixed fuel(old fuel for my previous outboard). and i and another 30L #91 in the tank before went on the water.

Back ground:
i thought this outboard privately but the outboard was siting at one of the marine shops(their customer having private sell).
the outboard was having heaps smoke come out and the technician solved it out by cleaning the carb. they told me couple of the air ways were blocked.
it was just a mass!!!please help
any information regard to this topic is appriciated.
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I am not familiar with the Valvoline NMMA oil. Is this 2 cycle oil or is it regular engine oil? It sounds like you put in regular engine oil and therefore it won't burn and it ended up coming out of the exhaust. It also caused your engine to lose power.
 
I really didnt think a 1986 powerhead would of fit up to 200hp HPDI mid... But I am really not sure...
Now, as far as your oil light/alarm problem goes... Check your oil tank inside the engine first, that should be almost full. If its not, you either have a oil controller, electric oil pump, or wiring issue...
But back to basics, start with a compression test, followed by a spark test... Let us know the results...
And if possible, post a few pics of the powerhead with the cover off, so we can see what exactly you have there....
 
really appriciate the replies. i will try to get more photos asap. as only time i can work on my boat is weekends.
and the oil i was using was definitely the oil used for 1:50 mixture as i was using it on a evinrude 35hp without any problem.

i m sure there is a wiring issue as there is green wire come out the remote control is broken. i just purchased a workshop manual and waiting for it to arrive.

thanks again for the help, i feel bit better as i was feeling so helpless.
 
boat 032.jpgboat 027.jpgorboat 029.jpgboat 028.jpgboat 030.jpgboat 031.jpg
sory for the late reply, i just got time to open the cover to take some photos today.
i also started the engine. It idles ok but once i tried to run some rev, the problem remains.

there are white smokes come out from the propeller and once i push the throttle,
the rev refused to go up and make loud backfires, cant see the flames thou(if on cars, they can be seen right?).

i did remove the spark plug lead one by one while the engine is idle and it seems the engine rev drop a little and vibrate more once each one is removed.
so i m pretty sure 6 cylinders are all working.

so, please analysis for me and really appricate any help regarding to my YAMAHA.

i also had the manual and i m reading it really hard now!!!
 
Looking at your pics, it does look to be consistant with a 1986 175hp....
If you have compression and a cylinder drop test shows up good as your results say... Thats a good start...
A couple of things to check first... Make sure your timer base rotates properly... And pull your main jets out to make sure they are clean... You dont need to remove the carbs to do this... The jets are the 12mm brass plugs that screw into either side of each bowl on the carbs...
I feel your problems are in your warning circuit though... If something is triggering your warning system, it is also putting your engine into slow mode...
This means that your ignition is limiting your engine speed to about 2500rpm by misfiring the ignition...
Best solution would be to sort out your wiring and warning system first...
If you want to do a quick test, disconnect the pink wire that goes to the powerpack and it should run ok if the warning sysytem is activating slow mode...
 
Back fires = incorrect timing or not enough air getting into the cylinders. For the air issue check your choke make sure it's not stuck in a close position. I suggest you remove the spark plugs and try to read them. Smokes coming out of the exhaust means too much oil in the cylinders. Adding premix fuell into your tank doesn't help. Can you get a small external fuel tank and try to hook up to your motor? Lastly, can you get a time light and recheck your timing?
 
thanks alot for the reply above. you talking about there is sort of rev limiter thing to limite the rev when something wrong. in my case, the beeping noise.
but i checked the manual, it did not mention anything about the limiter. do you sure about the rev limiter thingy?

i will check the timing and let you guys know about it.

thanks again. that's really helping. cheers

ONE more thing to ask, i think my Chock Soliniod is stucked, the switch at remote is not working, and the solinoid can be either pull out or pushed in.
so which is which, i mean, if the little shaft come out from the solinoid is at fully extended position, does it mean the chock is open or close.
 
When you get a beeping noise, this also triggers a rev limiter... sometimes when the beeper doesnt work, people assume the engine isnt running properly because the rev limiter kicks in...
When the choke plunger is out, your choke shutters should be open, also referred to as the run position.
Plunger in, choke shutters should be completely closed...
 
This is the way I understand it with newer motors: When the motor is over heated it retarted the timing and so the motor won't make power. This way it won't kill the power head. I have a 2004 motor and it did this. I could only limp back to the dock and it didn't over heat. It turned out the water pump was bad. My 86 and 88 90HP Yamahas don't have any of these controls when they over heated. Your motor is higher HP so it might have something I am not sure. From what you described I doubt your motor is over heated. You have to run it in higher RPMs for a bit without water to over heat. So I think it's timing related. So I suggest you to read the manual and check your timing per the manual. GL
 
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